validate.rb

require 'net/http'
require 'json'
require "base64"

file = File.read('/Users/paulo/Downloads/receipt')

contents = Base64.encode64(file)

def validate_receipt_remote(receipt_base64)  
  receipt_base64.gsub! ' ', '+'
  receipt_base64.gsub! '\n', ''
  receipt_base64.gsub! '\r', ''
  params_json = "{ \"receipt-data\": \""+receipt_base64+"\", \"password\": \"72efedb48c6a40729f0dc0b185484080\"}"
  uri = URI("https://buy.itunes.apple.com") # Use "https://buy.itunes.apple.com" for production
  
  Net::HTTP.start(uri.host, uri.port, :use_ssl => uri.scheme == 'https') do |http|
    response = http.post('/verifyReceipt', params_json)	    
    return JSON.parse(response.body)
  end
end

validate_receipt_remote(contents)